Acetalization of Glycerol with Citral over Heteropolyacids Immobilized on KIT-6

Glycerol acetalization with citral was studied using a heteropolyacid (tungstophosphoric acid) supported on KIT-6, as a catalyst, at 100 °C. Different catalysts were synthesized. Catalysts were characterized by scanning electron microscopy (SEM), inductively coupled plasma (ICP), X-ray diffraction (XRD), attenuated total refletion-Fourier transform infrared spectroscopy (ATR-FTIR), and potentiometric titrations. At a fixed time, the glycerol conversion increased with the H3PW12O40 (PW) on KIT-6. PW4-KIT-6 material had a higher conversion than other catalysts. The optimization of glycerol’s acetalization with citral was studied under the PW4-KIT-6 catalyst. After 5 h, it was found that, at T = 100 °C, with m = 0.3 g of solid, molar glycerol:citral = 1:2.25, the conversion of glycerol was 89%. Moreover, the PW4-KTI-6 catalyst showed good catalytic stability.

MSSA: Constant Time State Search through Multi-Scope State Area

In the stateful data plane, the switch can record the state and forward packets based on the local state. This approach makes it possible to integrate complex network applications into the data plane, thus reducing the amount of communication required between the switch and the controller. However, due to the time it takes to look up the state for packets, packet-forwarding latency has increased. With increased network traffic, a large number of states may be recorded in the switch, and the problem of increased packet-forwarding latency caused by the lookup state becomes more serious. In this paper, we propose the multi-scope state area (MSSA) for recording state inside the switch, which can achieve a fixed-time state lookup in a large-scale state. MSSA divides the state sharing scope by associating with the switch’s multiple match–action tables, and the shared scope is used to determine the state area for recording state. When processing a packet, the state required will only be in a limited number of states that are recorded in a few state areas. We implemented a prototype pipeline that supports MSSA based on Intel’s DPDK framework and investigated the effect of state type, number, location, and comparison method on state search/insertion time. The results show that the cost of MSSA search state is constant, regardless of the number of states, and MSSA has a high space utilization rate.

Fixed-time Active Disturbance Rejection Consensus Tracking Control of A Multi-Agent System via Event-Triggered Mechanism

A fixed-time active disturbance rejection control (FTADRC) consensus tracking strategy is proposed for a class of non-affine nonlinear multi-agent systems with an event-trigger-based communication. Non-affine followers are transformed into affine ones by combining the implicit function theorem with the mean value theorem. A distributed event-triggered estimator is introduced based on its neighbor output information. It is for estimation of a leader’s signal for parts of followers, who are not able to access the leader signal in a direct manner. A distributed FTADRC control strategy is then developed via an event-triggered communication in the framework of backstepping technology. With the help of the fixed-time control, the settling time of an MAS is assignable and independent on initial conditions. Extended state observers and tracking differentiators are employed to compensate unknown dynamics of each follower in real time and estimate derivatives of virtual control laws, respectively. It is proven theoretically that the MAS achieves input-to-state practically stability and the consensus tracking error converges to a neighborhood around the origin in a fixed time. Also, Zeno behavior is excluded. Finally, two examples are performed to illustrate the effectiveness of the proposed strategy.